🎨 Palette: Make sitrep modal trigger fully accessible

[0m364]

💡 What: Added role="button" and aria-haspopup="dialog" to all <a href="#" id="sitrep-btn"> modal triggers, and updated modal.js to respond to the Spacebar key by opening the modal and preventing default page scrolling.

🎯 Why: Using anchor tags (<a>) as modal triggers without proper attributes breaks accessibility. Screen readers announce them as links instead of buttons, and native anchors only trigger via the Enter key. Keyboard users and screen readers expect buttons (which these logically are) to respond to both Enter and Spacebar.

📸 Before/After: Visuals remain exactly the same (this is purely an accessibility/semantic change).

♿ Accessibility: Ensures that keyboard-only users can correctly trigger the OSINT modal using the spacebar, and screen reader users hear it announced properly as a button that opens a dialog.

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PR created automatically by Jules for task 2346592942167315568 started by @0m364

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